Guidewires are well known for placing and guiding catheters and other devices in the vascular network of the human body. In a common type of procedure a guidewire is inserted percutaneously into an easily accessed blood vessel. The guidewire then is manipulated to steer the guidewire through the vascular network until the distal end (the end inside the patient) reaches a desired location. The catheter may be inserted preassembled with the guidewire or the catheter may be inserted and advanced over a previously placed guidewire.
The steerability of the guidewire is important especially when a tortuous path must be navigated to reach the target site as is commonly encountered when placing a catheter in the coronary arteries. Steering is executed from the proximal end of the guidewire (outside of the patient) by rotating, pushing and pulling on the guidewire to cause corresponding movement at the distal tip of the wire. The distal tip typically has a slight bend so that when rotated it can be directed toward a selected one of several vascular branches. The distal tip of the guidewire typically is radiopaque so that its movement can be observed under x-ray fluoroscopy. Steering of the guidewire directly by hand has proven difficult because of the small diameter (0.010" to 0.038") and high flexibility of the guidewire. In addition some guidewires have a lubricious surface coating and tend to slip out of the user's grasp.
Steering tools have been developed to alleviate the foregoing problems. Typical is a device sold under the trade designation Steering Handle by U.S.C.I., a division of C.R. Bard, Inc. The device includes a hollow cylindrical body having a central bore and tapered collet for firm attachment to the guidewire. The device is substantially greater in diameter than the guidewire and is more easily gripped and rotated. The device is threaded onto the guidewire over an end of the guidewire and is slid along the guidewire to a location convenient for the physicians. The collet then is tightened securely around the guidewire.
To avoid having to slide the steering tool along the guidewire, laterally mountable steering devices have been developed. U.S. Pat. No. 4,726,369 discloses a steering tool including a resilient cylindrical body with an axial bore and a surrounding sleeve. Radial, longitudinally extending slots on the sleeve and the cylindrical body are aligned to form a continuous slot through which the guidewire can be laterally inserted and removed. To hold the guidewire in place, the sleeve is squeezed causing the resilient cylindrical body walls to compress against the guidewire. The device disclosed in U.S. Pat. No. 4,726,329 is not well suited for use when the traditional longitudinal mounting procedure is required or preferred.